A few seconds into a plank, the shaking starts. It can feel alarming, as if something’s about to give way. But shaking is one of the most useful signals your body gives you during a plank, once you know how to read it.

What’s happening when you shake

Your muscles are made of many small units that switch on and off to hold you steady. As some of them tire, your body brings in fresh ones to keep you up. That handover isn’t perfectly smooth, which is what you feel as shaking. Research shows shaking tends to build gradually during a hold and increase more sharply as you get close to your limit.

Shaking isn’t a reason to stop on its own

A little shaking means your muscles are working hard enough to make progress. It doesn’t mean anything is being harmed. The signal to stop is when your shape starts to change, like your hips dropping, not the shaking itself.

Reading the signal

You could think of shaking as a rough guide to where you are in a hold:

• No shaking: you’re well within your comfort zone.
• Light shaking, steady shape: you’re working well.
• Strong shaking, shape starting to slip: time to finish the hold.

Shaking that comes later

As your trunk muscles build staying power, many people notice the shaking starts later in the hold, or feels milder. That’s real progress, even if your total time hasn’t changed yet.

Something to try this week

In one plank each day, you could notice roughly when the shaking starts. Keep a note of it. Over the coming weeks, seeing the shaking start later is a sign you’re getting stronger.

What to take away

• Shaking happens as your body swaps tired muscle units for fresh ones.
• Light shaking with a steady shape means you’re working well.
• Stop when your shape slips, not just because you’re shaking.
• Shaking that starts later is a sign of progress.

‍